The Potter Model MBA-DC electric Bells are vibrating type bells designed for use as fire, burglar or general signaling devices.
They have low power consumption and high decibel ratings. The unit mounts on a standard 4" (101mm) square electrical box for indoor use or on a model BBK-1 weatherproof backbox or BBX-1 deep weatherproof backbox for outdoor applications.

More information can be found on the Potter Electrical Signal Company Website (www.pottersignal.com).